The invention relates to a system including an antenna device and feed device for transmitting and receiving RF waves. Specifically, it relates to a system for a mobile radio communication device, e.g., a hand-portable telephone, which is capable of both transmitting and receiving on multiple separate frequency bands.
In the communication services today it is an increasing demand for availability and small sizes of the user units. A user of a hand-portable communication unit wishes to be reached wherever his location may be. This puts requirements on the operators to provide for good coverage of their mobile networks. For areas with few users, e.g. in low-populated areas, at the countryside, or at sea, it is uneconomical or impossible to provide for good coverage by means of terrestrial mobile phone systems. For such areas, good coverage can be obtained by means of communication via satellites. Since communication with linearly polarized RF waves, which are used in the terrestrial mobile communication systems, requires a certain degree of alignment between the transmitting and receiving antennas, this type of signals are unsuitable for satellite communication. Instead circularly polarized RF waves are used. This means that a special type of antenna has to be used. It is practical when the same mobile telephone can be used for both satellite communication and terrestrial communication. To obtain this, telephones have been provided with two antennas.
This does not comply with the demands on antennas for hand-portable telephones, to be compact, and to occupy a small space.